There are two studies that provide the data for this project. The study based on the Honolulu Asia Aging Study is designed as a nested case control study and all cases of dementia identified in exams 4 and 5 of the Honolulu Asia Aging Study, cases of mild cognitive impairment (defined as a drop in CASI score of >4pts per year), a random set of controls frequency matched in 5-year strata to the cases. The second study is the Age Gene/Environment Susceptibility - Reykjavik Study of men and women born between 1907 - 1935 in Reykjavik, Iceland. Together these studies have unique and rich data on brain function and structure. We are currently conducting association studies of polymorphisms for inflammation and vascular disease in relation to the risk for dementia and other related outcomes in brain aging. The genotyping is the same in both studies